My very first post! I ride a 1991 ST with 86000 miles. I discovered an oil leak on the ground and when I traced it upward, it stopped at the left head gasket. After taking off all the plastic, gas tank, air box and carbs, it was easy to see the leak. I have both the Honda service manual and a Clymer as well. Following these publications I lined up all the timing marks, removed the timing belt, both cams then the head. Cleaned everything,replaced the head gasket, torqued the bolts, installed the intake cam and then I hit the wall. I cannot get the exhaust cam to sit in the head. The intake went right in with no issues but not so the exhaust. Have I done something backwards? Help!!!
blown head gasket
- Thread starter raybonz
- Start date
ST1100Y
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hmm, dumb question: did you set the engine to TDC as shown in the workshop manual prior removal of the head?
Did you keep that position during the work process, or incidentally move it?
You did note that the cam sided sprockets consist of two wheels being spring loaded/twisted against each other?
You might need to "straighten" them first with a big screwdriver to mesh properly into the reduction gear.
Also note the adjustment marks on both cams (again: as shown in the manual)
Did you keep that position during the work process, or incidentally move it?
You did note that the cam sided sprockets consist of two wheels being spring loaded/twisted against each other?
You might need to "straighten" them first with a big screwdriver to mesh properly into the reduction gear.
Also note the adjustment marks on both cams (again: as shown in the manual)
In answer to your question, yes, everything is at TDC according to the Honda manual. But since I removed the timing belt to remove the head, nothing else was moved. On the right side cams there are index marks to line up. On the left, punch marks. All of which I made sure of prior to removing the belt. I did see the two sprockets you mentioned and on the intake cam once it was lined up with the punch marks then snugged down, they lined up on their own. The cam lobes are coming in contact with the lifter and will not seat at all. I'm puzzled about "adjustment marks" on the cams. Can you tell me where there're at?
I think he's talking about the same index/punch marks you have mentioned.
At #1 TDC the cam lobes of the other 3 cylinders are not necessarily pointing away from the valve buckets. When you remove them its not always obvious that certain valves were compressed a bit as you gradually release the bolts on the bearing caps. To reassemble you put the cam back into place as best you can, centered within the bearing caps, then gradually tighten all the bolts in sequence and the cam will go back into its original position and compress the required valves as necessary.
I'm trying to remember from my last valve adjustment if the cams should both just drop into place with no interference, and can't remember for sure, but I don't think they should. I believe what you're seeing is typical, and you probably have all the timing marks aligned properly (double/triple check to make sure). Hopefully someone else can confirm my statement with regards to the ST1100, but I know with other bikes the method described above usually applies.
JPrieST
Don't squat with your spurs on
What you described here matches my experience a few months back when I had to adjust my valves. One cam sat a bit "proud" and had to be pulled down when tightening the caps. (from memory I would guess about 1/4 inch +/-) Be very careful to tighten each bolt in sequence just 1/2 turn or so at a time. You will notice very little resistance as it pulls the cam in place. In other words you should be able to turn the wrench or ratchet with one finger quite easily on each bolt as it draws it down until the bearing caps are seated. Any more resistance than that and you do have something wrong.
Thanks for the info Joel, but my problem turned out to be not setting the correct timing marks. As soon as I did that, the cams fell right into place. I got everything back together and after a little cough she started right up! Felt good knowing I did the work. While it was running I noticed a fuel leak at the petcock-very frustrating. But then I looked here in another forum and found others who have also had this problem and the remedy for it. Again feeling very good I went for the test ride and it went great! Until the valve cover gasket blew and oil went all over everything! Got a new gasket today and will try all over again. The odyssey continues........
Hmmm, the valve cover gaskets will often weep, but blowing oil all over everything sounds a bit unusual. If you can't find an obvious large crack in the gasket to explain the rapid oil loss (or can you?) you may want to look into whether you may have crankcase pressure building up somehow.
BTW, not sure if you've noticed, but the ST valve cover bolts have a shoulder on them that only allows you to put a certain amount of force on the cover. The variable is the thickness of those grommets that sit under the heads of the valve cover bolts. As the grommets compress over time you'll be limited as to how tight you can get the cover to seal, even with a new gasket. So you may want to consider picking up a new set of those grommets as well.
ST1100Y
Site Supporter
I second that...
And to prevent any seeping I normally replace both, gaskets and grommets during a valve check...
To ease installation I glue them in place on the covers (only a thin layer of Pattex), prevents them from falling off on the (unseen) inboard side).
Thanks for the helpful tips and I seem to remember that my 2000ST had a weeping valve cover gasket. But this one suffered from a lack of any sealant around one of the "half moons" on the head side of the gasket. I was sure that all surfaces were covered but obviously missed that area all together. I'm going on a test ride in the morning and I'm hoping all goes well. What surprised me though was the pressure in that area. I wouldn't have thought it would be enough to push the gasket out like that. After all is said and done, I'm really getting to know my bike better and understanding the systems. This site has helped so much and thanks to all that have chipped in. It' great that no matter what problem I may encounter, someone else has already gone through it and posts their experiences.
Again, this doesn't sound normal, check for a plugged crankcase breather.
Putting a little sealant on the gasket helps with the weeping, but isn't always necessary even for that. If you blew the half moon out of its position, then there's another issue that you need to address, its not due to a lack of sealant.
John OoSTerhuis
Life Is Good!
I agree. Sounds like the crankcase breather hose has been mis-routed/connected or kinked/capped somehow. Unusual but not unheard of (right, Vinny?
). I know of two instances of the hose being mistakenly connected to the carb float bowls drain manifold during reassembly. Unique to the 1991s, the crankcase breather hose comes from the right rear engine area (external crankcase breather chamber), up into the engine 'V' and connects to the nipple on the bottom right side of the air cleaner housing.
Let us know what you find out. Good luck.
John
PS - Other known cases of oil blowing out the valve cover gasket involved a rag left stuffed in the oil drain hole in the head during a valve shim R&R.
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Yeah, same thing ,same place. This time I didn't make it out of the driveway. And the half moon had plenty of sealant this time so your right. I was thinking about the new head gasket maybe being the wrong one. Do you know if all the 1100's are the same engines? Except for the 40amp alt., were there any changes in cylinder head configuration? But the crankcase breather is first on my list. Thanks!
John OoSTerhuis
Life Is Good!
There are some differences between USA 1991 engines and all other years (crankcase breather related) but TTBOMK the head gaskets are the same for all years. Check a few model years' online fiches to confirm that they all have the same part number that you have.
John
John
I guess its too late to ask if you compared it to the old one before putting it on, but its very unlikely the gaskets are different, so not a big deal. Like John suggests, check the part numbers for peace of mind, but I wouldn't expect them to be different.
With the breather hose blocked the crankcase pressure is going back into the head through the oil drain passages. In addition to blowing out your valve cover gaskets, its also potentially putting stress on your new head gasket as well, through the same oil drain passages. So go ahead and trace down the cause of the blockage, John gave a few ideas in his previous posts.
Well John, you can add me to the list of hooking up the breather hose to the carb drain too! I took the tank out this morning and looked in the valley and big as day, there was the breather hose. But I couldn't see the carb drain line. I think that's why I connected the breather hose to the carbs. When I moved the carb shield, I found the drain hose hiding underneath. So after reassembly then warm-up, I went for a test ride of 5 miles. No leaks, ran great and now she sits overnight to see if everything is still good tomorrow but I think all will be good. Thanks to you both for all the help!
ardykay54
Russ "NeonMan" Knock
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John O. is like McDonalds...............He has millions of satisfied customers!! Russ.
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Well glad you got it all sorted out and there was no major problems. Now go out and enjoy a good ride!!
John OoSTerhuis
Life Is Good!
Whew! And now there are three. Murphy's Law, Second Corollary confirmed.
John, you saved my bacon! I let my girl sit overnight and was excited to find no leaks in the morning. So off to work I went. 40 miles of twisty bliss later, I noticed she was a little hot. No big deal since it was 107 in Santa Clarita at 1500 in the afternoon. When I left work at 0030 it was in the 70's and kind of humid but still great riding weather. Half way home though my legs were roasting and the plastic was very hot to the touch. The temp never reached the red but neither did it go down to where it usually sits. It's never run hot even when the outside temp was triple digits. The cooling system seems pretty simple but is there a component that fails more common than most? Just wanted to add, I was born in Iowa City myself.
Check the coolant level (at the radiator filler neck) and make sure its correct. While you're in there check the condition of the overflow hose from the filler neck. If that's OK then I'd guess its time to replace the t-stat.